//
// Author:
//   Jb Evain (jbevain@gmail.com)
//
// Copyright (c) 2008 - 2015 Jb Evain
// Copyright (c) 2008 - 2011 Novell, Inc.
//
// Licensed under the MIT/X11 license.
//

using System;

namespace MonoFN.Cecil.Metadata
{
    internal sealed class BlobHeap : Heap
    {
        public BlobHeap(byte[] data) : base(data) { }

        public byte[] Read(uint index)
        {
            if (index == 0 || index > data.Length - 1)
                return Empty<byte>.Array;

            int position = (int)index;
            int length = (int)data.ReadCompressedUInt32(ref position);

            if (length > data.Length - position)
                return Empty<byte>.Array;

            var buffer = new byte [length];

            Buffer.BlockCopy(data, position, buffer, 0, length);

            return buffer;
        }

        public void GetView(uint signature, out byte[] buffer, out int index, out int length)
        {
            if (signature == 0 || signature > data.Length - 1)
            {
                buffer = null;
                index = length = 0;
                return;
            }

            buffer = data;

            index = (int)signature;
            length = (int)buffer.ReadCompressedUInt32(ref index);
        }
    }
}